An image processing apparatus which performs dithering to an input image, includes: an input value storage unit which stores an input value to generate a mask seed value corresponding to a single pixel in a unit area among a plurality of pixels displaying an image, wherein the unit area includes a first line and at least second line; and a seed value generator which generates the mask seed value corresponding to one of pixels in the at least one second line among the pixels of the unit area based on the input value stored in the input value storage unit.